JP5021625B2 - Patient monitoring system - Google Patents

Abstract

The present invention relates to a patient monitoring system, a patient monitoring method and a computer program. In order to improve the monitoring of patients, particularly for cardiac monitoring and weight monitoring, a patient monitoring system ( 1 ) is provided, the system comprising a number of force sensors ( 2 ) assigned to a patient's bed ( 3 ), the force sensors ( 2 ) being adapted for generating first signals corresponding to a first force component, the force sensors being further adapted for generating second signals corresponding to a second force component, the second force component not running parallel to the first force component, and the system further comprising an analyzing module ( 4 ) adapted for deriving from said signals data corresponding to the patient's condition.

Description

  The present invention relates to a patient monitoring system, a patient monitoring method, and a computer program.

  Monitoring patients during sleep is a standard tool in many situations, mainly in hospital environments. Depending on the diagnosis, different parameters are monitored. Frequently required parameters are weight, heart rate, respiratory rate, and respiratory abnormalities, and special movement patterns during sleep. Measuring such a quantity usually requires great technical effort and multiple techniques.

  It is known to measure a patient's weight by incorporating a scale under or in the bed post. Furthermore, it is known to collect information on cardiopulmonary performance, for example by using pressure sensitive sheets in the bed. For example, International Patent Application WO 2004/045407 A1 describes an apparatus and method for patient monitoring regarding parameters such as body movement, body position, respiratory rate, and / or heart rate. The device and method uses a sensor device having at least two piezoelectric sensors provided on a surface, such as a bed, and the patient can be coupled to the device by simply laying the patient on the surface.

  In US 2003/0114736 A1 a system and method for patient monitoring is disclosed, where the patient's weight uses a force sensor positioned to measure the application of force to the patient's sleeping surface. Is detected. Motion by the patient during sleep is measured using an additional sensor.

  In US 2004/0046668 A1 an apparatus and method for patient monitoring is disclosed, wherein the patient's weight is detected using a weight sensing pad placed under each leg of the patient's bed. In addition, strain gauges are used to measure the deformation of the structural members of the patient's bed to obtain information about the patient's movement.
WO 2004/045407 A1 US 2003/0114736 A1 US 2004/0046668 A1

  The present invention aims to improve patient monitoring, particularly for cardiac monitoring and weight monitoring.

This object is achieved according to the present invention by a patient monitoring system. The system has a plurality of force sensors associated with the patient's bed. The force sensor is adapted to generate a first signal corresponding to the first force component and a second signal corresponding to the second force component, wherein the second force component is the first force component. It is not parallel to the force component. The system further comprises an analysis module adapted to derive patient weight and patient motion from the above signals .

The object of the present invention is also achieved by a patient monitoring method. The method is adapted to generate a first signal corresponding to a first force component and a second signal corresponding to a second force component that is not parallel to the first force component. Assigning a plurality of force sensors to the patient's bed and deriving the patient's weight and patient motion from the preceding signals .

The object of the invention is also achieved by a computer program. The computer program includes computer instructions that, when executed on a computer , derive patient weight and patient behavior from a plurality of signals. The data corresponds to the patient's condition and the signal corresponds to the first force component and the second force component. The second force component is not parallel to the first force component, and the force component is generated by a plurality of force sensors associated with the patient's bed. The technical efforts necessary according to the invention can thus be realized on the basis of the instructions of the computer program according to the invention. Such a computer program may be stored on a carrier such as a CD-ROM or may be available on the Internet or other computer network. Before being executed, the computer program is read from the carrier using a CD-ROM player or the like or loaded from the Internet and loaded into the computer and stored in the memory of the computer. The computer has, inter alia, a central processing unit (CPU), a bus system, memory means such as RAM or ROM, a flexible disk or hard disk unit, and storage means such as an input / output unit.

  The basic idea of the present invention is to provide a very simple and inexpensive solution to a combined measurement of patient weight and cardiopulmonary capacity. To achieve this goal, it is proposed to use a force sensor adapted to measure the force applied by the patient on the bed.

  In other words, the present invention uses multiple force sensors (one, two, three, or four force sensors) to measure and characterize patient motion and weight. Special patterns are extracted from these quantities using the analysis module, such as heart rate, respiration rate, special movements in restless leg syndrome, etc. In addition, the presence of the patient in the bed is inferred. It is essential to obtain the magnitude and direction information of the force vector to separate such different force signals.

  A variety of force sensors can be used with the present invention, such as strain gauges, piezoelectric devices, capacitive force sensors, and the like. Since a single type of sensor has to be used, a very simple system design can be achieved compared to solutions known from the prior art.

  A bed according to the present invention is defined as a surface or other device that rests or sits on a conventional bed, hospital bed, couch, conventional chair, dental chair, wheelchair, (surgical) table or the like.

  These and other aspects of the invention are further elaborated on the basis of the following examples, which are defined in the dependent claims.

  According to a preferred embodiment of the present invention, the force sensor is adapted to generate a first signal corresponding to the vertical force component, and further adapted to generate a second signal corresponding to the horizontal force. Is done. In other words, the patient monitoring system is adapted to resolve the measured force into a horizontal component and a vertical component. As a result, the patient's weight can be determined (mainly by using the vertical force component). Further, by separating the horizontal and vertical force components, patient motion can be determined (primarily by using horizontal force components). In the case of cardiac flexure measurement, the anisotropic nature of the cardiac motion toward the aorta while the patient is in the supine position delivers a large horizontal force component. Large horizontal force components are also typically provided by the movement of restless leg syndrome.

  Desirably, the analysis module is not only adapted to derive the patient's weight from the preceding signal. Additionally, sleeping heart rate and / or respiratory rate, and / or respiratory abnormalities, and / or special movement patterns can be determined.

  A plurality of force sensors is preferably associated with the plurality of bed posts. In such embodiments, when the analysis module is integrated into the bed, or data communication between the sensor and the analysis module and / or between the analysis module and the display unit or the like is wireless. In particular, no additional wiring or cables are required if given. Alternatively, the set of force sensors can be located at a technically equivalent location, such as between the mattress and the bed frame.

In another embodiment of the invention, the force sensors are arranged such that the planes of force application are not parallel to each other so as to distribute the effective force. In the basic arrangement, the force sensor is simply integrated into the bed post in a somewhat tilted arrangement. However, it has been found that the direction of the force component can be more easily analyzed when the force sensors are arranged such that the planes of force application are orthogonal to each other. In all cases, the nature of the sensor placement must be considered when deriving data corresponding to the patient's condition using the analysis module. In other words, an analysis module with equivalent means, preferably a computer or a microprocessor or the like, must be programmed accordingly.

  In yet another embodiment of the present invention, a plurality of force sensors are adapted to measure the measuring / shearing force. In this embodiment, the patient's movement can be determined particularly accurately. Piezoelectric devices are preferably used as force sensors for this purpose.

  These and other aspects of the invention are described in detail below with reference to the accompanying drawings and the following description by way of example.

  The patient monitoring system 1 has three force sensors 2 integrated into a bed post of a hospital bed 3. FIG. 1 shows the framework of such a bed 3 without a mattress. Three piezoelectric sensors are used as the force sensor 2. With three force sensors 2, a complete three-dimensional force model can be reproduced using the monitoring system 1. The force sensor 2 is used to measure the force applied on the bed 3. For this purpose, the force sensor 2 is positioned so that the planes of application of the forces are orthogonal to each other. In other words, the horizontal and vertical components of the force are established. Each force sensor 2 generates a signal depending on the effective force. Since the piezoelectric power sensor 2 is used, the generated signal is a voltage signal corresponding to the deformation of the piezoelectric layer. The first signal is generated when a vertical force component is detected, and the second signal is generated when a horizontal force component is detected. The signal generated corresponds to the magnitude and direction of the associated force component.

  The patient monitoring system 1 further has an analysis module 3. The analysis module 4 is attached to the skeleton of the bed 3. The signal from the force sensor 2 is transmitted to the analysis module 4 over the wireless communication path based on Bluetooth wireless technology. The analysis module 4 is adapted to receive measurement signals and to derive data corresponding to the patient situation from such signals. The resulting data is communicated to an external receiver 5 connected to a monitor 6 that displays the data. Other display methods are possible. The measured signals and / or data may be stored in the analysis module and / or in the external receiving unit 5 and / or some other unit connected to the patient monitoring system 1. For the purpose of deriving patient-related data, the analysis unit 4 has a computer adapted to execute a computer program to derive such data from the amount of signal measured. The computer has input and output interfaces for data transmission.

  The analysis unit 4 applies a computer program to the signal corresponding to the vertical force component to determine the patient's weight. Furthermore, the analysis unit 4 determines horizontal and vertical force configurations so as to determine the patient's cardiopulmonary capacity, in particular to determine the heart rate, the respiratory rate and, of course, whether or not the patient is present in the bed 3. Use signals that correspond to both elements.

  In FIG. 2, a force sensor 7 is shown (left figure) which is mounted horizontally in a bed post 8 known from the prior art. In this case, only the vertical part of the force 9 acting on the bed post 8 can be determined (right figure). The effect of the force 9 on the sensor 7 is schematically illustrated as a reduced sensor thickness.

FIG. 3 shows two sensors 10, 11 according to a first embodiment of the present invention. The first force sensor 10 is tilted and positioned on the first bed post 12, and the second force sensor 11 is positioned on the second bed post in the same manner. That is, the force sensor 10 and 11, so that the plane of application of force is KuTadashi exchange such are parallel to one another, are arranged. When no force is applied, the force sensors 10, 11 are unloaded (left figure). When the patient is in bed 3, force 9 is applied on the bed frame and all four bed posts. In this case, there is a patient motion resulting in a force component towards the second bedpost 13 while there is no force component towards the first bedpost 12 (right figure). As a result, the force sensor 11 at the second bed post 13 determines the force component and generates an associated signal. The signal has the magnitude of the force component. The sensor 11 communicates a signal with a sensor ID (identifier) to the analysis unit 4. The analysis unit 4 identifies the geometry of all force sensors. From the sensor ID, the received signal must be associated with the sensor 11 of the second bedpost 13 and that the received magnitude must be associated with the effective plane of force corresponding to this bedpost. The computer program executed in the computer of the analysis unit 4 processes a complete three-dimensional model of the applied force Patient related data (weight, heart rate etc.) is obtained from the processing of such data.

  FIG. 4 shows a second embodiment of the present invention. This embodiment is based on torque measurement. The piezoelectric layer 14 is provided with two piezoelectric elements (sensors) 15 and 16. The piezoelectric layer 14 is positioned between the upper portion 17 and the lower portion 18 of the bed post. The piezoelectric elements 15 and 16 are arranged so that the upper portion 17 of the bed post is coupled only to the second piezoelectric element 16, while the first piezoelectric element 15 remains uncoupled (left figure). Patient motion causes a torque to be applied to the bedpost that results in an asymmetric deformation of the piezoelectric layer 14. As a result, the torque is connected to a signal generated by the second piezoelectric element 16, while there is no signal generated by the first piezoelectric element 15 (right figure). Since the torque also depends on the horizontal component of the applied force, the analysis module 4 can determine not only the vertical component but also the horizontal component of the force from the generated signal.

  FIG. 5 shows a third embodiment of the present invention. This example is based on the measurement of shear forces. Again, the piezoelectric layer 20 is provided with two piezoelectric elements (sensors) 21, 22, which are positioned between the upper part 17 and the lower part 18 of the bedpost. The first piezoelectric element 21 is positioned on top of the piezoelectric layer 20 and is coupled to the upper portion 17 of the bed post, while the second piezoelectric element 22 is positioned laterally with respect to the piezoelectric layer 20. Is done. In other words, the first piezoelectric element 21 is adapted to measure only the vertical force component and the second piezoelectric element 22 is adapted to measure only the horizontal force component (left figure). When there is a patient motion purely connected to the vertical force, only the first piezoelectric element 21 generates the relevant signal (right figure), and when there is a patient motion purely connected to the horizontal force, the second piezoelectric element Only 22 generates the relevant signal. However, if there is a horizontal force component as well as a vertical force component, both piezoelectric elements 21, 22 generate a signal so that the analysis module 4 can distribute the effective force.

  FIG. 6 shows a fourth embodiment of the present invention. The different planes used for force measurement are here realized in a single bed post. For this purpose, a single sensor module is provided and positioned on a single bed post of the bed 3. In contrast to the arrangement shown in FIG. 1, the other three bed posts do not have force sensors.

  The sensor module has three force sensors 23, 24, and 25 (see FIG. 7). The upper part 17 and the lower part 18 of the bed post are conical and fit against each other. In between there are three force sensors 23, 24, 25 arranged to provide measurements along an orthogonal plane as shown in FIG. The three piezoelectric layers 26, 27 are positioned between the upper portion 17 and the lower portion 18 of the bed post, and a plurality of piezoelectric elements (sensors) are provided for each effective plane. If there is no action, no signal is generated (left figure). For example, if a horizontal force component 28 is applied against the upper portion 17 of the bedpost by pushing the upper portion 17 to the right, one piezoelectric layer 27 is compressed and the associated signal is It is generated by the piezoelectric element 29. At the same time, the other piezoelectric layer 26 is enlarged, leading to the generation of related signals by the piezoelectric elements 30 of the layer 26. The analysis module 4 derives the desired data from these two signals.

  FIG. 7 is a plan view of this arrangement. The form described is merely an example. Other geometric arrangements are possible.

  Of course, the present invention can be applied not only to patients but also to healthy humans or animals.

  It will be apparent to those skilled in the art that the present invention is not limited to the details of the illustrative embodiments described above, and that the present invention can be implemented in other specific forms without departing from its spirit or essential characteristics. it is obvious. Accordingly, the examples are considered in all respects to be illustrative rather than restrictive, and the scope of the invention is indicated by the appended claims rather than by the foregoing description, and is therefore equivalent to the claims. All modifications within the spirit and scope are included therein. Further, the word “comprising” does not exclude other elements or steps, and the word shown in the singular does not exclude the presence of a plurality, but a single element such as a computer system or other unit It is clear that can fulfill the functions of several means recited in the claims. Any reference sign in a claim should not be construed as limiting the claim concerned.

1 is a schematic diagram illustrating a patient monitoring system according to the present invention. FIG. 1 is a schematic cross-sectional view of a force sensor located at a bed post as known from the prior art, where the force sensor is first unloaded and then loaded. FIG. 2 is a schematic cross-sectional view of two force sensors located at different bed posts according to the present invention, where one force sensor is first unloaded and then loaded. FIG. 2 is a schematic cross-sectional view of a force sensor disposed on a bed post according to the present invention, where the force sensor is first unloaded and then loaded. FIG. 4 is a schematic cross-sectional view of another force sensor disposed on a bed post according to the present invention, where the force sensor is first unloaded and then loaded. 1 is a schematic cross-sectional view of a force sensor module disposed on a bed post according to the present invention, the force sensor module having three force sensors, the force sensor being first unloaded and subsequently loaded. FIG. 7 is a schematic plan view of the force sensor module shown in FIG. 6.

Claims (8)

A patient monitoring system,
Having a plurality of force sensors associated with the patient's bed;
The force sensor is adapted to generate a first signal corresponding to a first force component and a second signal corresponding to a second force component, the second force component comprising: Not parallel to the first force component,
The patient monitoring system further have a analysis module is adapted to derive data indicating the state of the patient from the signal,
The patient bed includes a first bed post including a first force sensor and a second bed post including a second force sensor, wherein the first and second force sensors are A force application plane tilted with respect to a plane defined by a patient bed, the force application planes of the first and second force sensors being orthogonal to each other patient monitoring system to be. The patient monitoring system of claim 1, wherein the analysis module is adapted to derive a weight of the patient. The patient monitoring system of claim 1, wherein the analysis module is adapted to derive a motion of the patient.   The patient monitoring system according to claim 1, wherein the analysis module is adapted to derive a heart rate and / or respiratory rate and / or respiratory abnormalities and / or special movement patterns of the patient from the signal.   The patient monitoring system of claim 1, wherein the plurality of force sensors are associated with a plurality of bed posts.   The patient monitoring system of claim 1, wherein the at least two force sensors are arranged to form a composite sensor module to be positioned on a single bed post. A patient monitoring method,
A plurality adapted to generate a first signal corresponding to a first force component and a second signal corresponding to a second force component that is not parallel to the first force component. Assigning a force sensor to the patient's bed;
Deriving data indicative of the patient's condition from the signal;
I have a,
The patient bed includes a first bed post including a first force sensor and a second bed post including a second force sensor, wherein the first and second force sensors are A method having a force application plane tilted with respect to a plane defined by a patient bed, wherein the force application planes of the first and second force sensors are orthogonal to each other . A computer program,
Having computer instructions for deriving data from a plurality of signals when the computer program is executed on a computer;
The data corresponds to a patient condition, the signal corresponds to a first force component and a second force component, and the second force component is relative to the first force component. The force component is generated by a plurality of force sensors associated with a patient bed, the patient bed including a first bed post including a first force sensor, and a second A second bed post including a force sensor, the first and second force sensors having a plane of force application tilted with respect to a plane defined by the patient's bed; A computer program , wherein the planes of application of the forces of the first and second force sensors are orthogonal to each other .

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